Image forming apparatuses, such as copiers, printers, facsimile machines, or multifunction printers having at least one of copying, printing, scanning, and facsimile functions, typically form an image on a recording medium (e.g., a sheet) by a liquid discharging method. Thus, for example, a liquid discharging head discharges liquid (e.g., an ink droplet) onto a conveyed sheet, and the liquid is then adhered to the sheet to form an image on the sheet.
Such image forming apparatuses generally employ either a serial-type image forming apparatus or a line-type image forming apparatus.
A serial-type image forming apparatus feeds recording media of paper intermittently in a sub-scanning direction, and, when the recording media are stopped, moves a recording head, which includes the liquid discharging head thereon, on the recording media in a main scanning direction perpendicular to the sub-scanning direction. In the serial type image forming apparatus, a recording head is mounted on a carriage that moves reciprocally along a guide rail disposed perpendicular to a direction in which the recording medium is transported, and recording is carried out while reciprocating the recording head along the guide rail.
By contrast, in the line-type image forming apparatus, a recording head that is as wide as the recording medium is disposed in a direction perpendicular to the direction in which the recording medium is transported, and recording is carried out line by line.
These image forming apparatuses employ ink cartridges to store ink for supplying the ink to the recording head. These ink cartridges are of various types, as described below.
One proposed type of an ink cartridge includes a cartridge case and an ink bag accommodated in the cartridge case. The cartridge case has an opening formed corresponding to an opening formed on the ink bag. A ring-shaped projecting portion that projects outward from an outer surface of a perimeter of the opening of the case is formed around the opening of the case. The outmost part of the opening of the case is positioned relatively outward from a leading edge of the opening of the ink bag.
The ink cartridge of this proposed approach is assembled by one ink pack with ink therein, two cartridge cases, and two screws by slidably fitting the two cases together and fixing with the two screws only. Therefore, even if the ink cartridge with a certain amount of ink contained in the ink bag falls, the configuration gives relatively small damage to the case, and thereby prevents ink leakage from the ink bag containing the ink therein. Further, the configuration does not employ a snap-fit mechanism, which can expect high reusability.
However, the ink cartridge of this proposed approach may increase an amount of ink contained in the ink bag. When an ink cartridge is made relatively large and heavy due to an increase in amount of ink and when an ink cartridge falls from a higher place to give a greater impact force to the ink cartridge, the impact can wobble the ink pack in the case, which can result in damage to the ink pack to cause ink leakage.
Another proposed approach of an ink cartridge provides an ink cartridge including a rigid case accommodating an ink pack formed by adhering respective perimeters of flexible films together.
The rigid case includes a recessed portion and a rib. The recessed portion corresponds to a cross section of the ink pack raised to a pillow-like shape due to ink filled therein. The rib is formed to nip the perimeter of the ink pack. The recessed portion maintains the ink pack in a substantially constant shape to prevent high deformation due to vibration and/or fall, and the rib positions and fixes the ink pack in the rigid case. According to this configuration, the ink pack can be removed easily by detaching the rigid case from the ink cartridge.
However, since the ink cartridge of this proposed approach cannot slidably fit the two cases together, if the ink cartridge becomes relatively large and heavy due to an increase in amount of ink and if the ink cartridge falls from a higher place and receives a greater impact force, the two cases may need to be more fixedly adhered to each other and need additional screws, which can increase manufacturing costs. In addition, an increase in claws used for engaging the two cases may increase steps or processes in preparing for reusing the ink cartridge.
To enable multiple printing for one replacement, there is market demand for an ink container capable of containing a large amount of ink. It is preferable that such ink container is collected for reuse for maintenance of global environment purposes.